Does the Torque Converter heat engine while idling??

66 Barracuda, 273/904.

I've noticed when idling in Park my engine temp will sit at 180* all day long. When sitting in traffic in Drive, the engine temp will increase above 180*. It won't go above 195*, but I'm curious to know what causes it to increase. Will the torque converter cause it?

I'm idling about 850 RPM in Park and 675 RPM in gear.

Thanks!